1. Field of the Invention
The present invention relates to a string-guiding structure for an automatic curtain-reeling device that has a movable guiding frame to define a limiting space to constrain movement of the string to avoid the string being caught on the reeling device.
2. Description of Related Art
A cordless curtain structure substantially contains an automatic curtain-reeling device on its top rail and makes the blades or curtain to elevate or lower by pulling the string with the automatic curtain-reeling device. Therefore, the cordless curtain structure is safe and convenient in operation.
The conventional automatic curtain-reeling device is composed of two paired guiding wheels meshed by gears. The top side of the two guiding wheels is mounted with an S-shape coil spring, and a bottom side of the two guiding wheels secures two strings winding in counteractive directions. The two guiding wheels with two pivotal shafts respectively and a connecting pin are sandwiched by an upper board and a lower board to compose a stable combination to extend the strings downward to collect the blades or the curtain for the pulling function. Although the user can pull and stop the blade or the curtain at any position, the moving speed of the string is fast (the diameters of the guiding wheels are small so that the rotation speed is fast). Thus, the strings easily get stuck, because the strings violently swing and rebound when they are pulling or collecting. In operation, the strings are wound on the guiding wheels respectively and repeatedly. When the strings are pulled outward or collected inward by rebounding of the S-shaped coil spring, the strings swing rapidly up and down because of the different locations where the strings are mounted on the guiding wheels. When the string swings upward, it easily enters the gear gaps to be caught by the gears. When one string swings downward, it easily falls into the seam between the automatic curtain-reeling device and the top rail and also gets stuck. Therefore, the automatic curtain-reeling device malfunctions in both situations abovementioned.